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Hello all. I discovered an oil leak in my 48k mile '07 GL450. Coming from high up on the back of the engine. Nothing is hitting the ground, but it's pooling on the cross member below the engine.
Here's the back of the engine, looking up from underneath it:
Zoomed in:
Seems to be coming from the round plug up high, although could be coming from above that and I can't see it. Any ideas what this is most likely to be? And while annoying to have a leak on such a low mileage vehicle, is it something that could lead to a catastrophic failure, or is it more of an annoyance factor?
THANKS!
Last edited by StradaRedlands; Feb 27, 2017 at 09:44 PM.
Hello all. I discovered an oil leak in my 48k mile '07 GL450. Coming from high up on the back of the engine. Nothing is hitting the ground, but it's pooling on the cross member below the engine.
Seems to be coming from the round plug up high, although could be coming from above that and I can't see it. Any ideas what this is most likely to be? And while annoying to have a leak on such a low mileage vehicle, is it something that could lead to a catastrophic failure, or is it more of an annoyance factor?
Can't tell for sure from the pictures, but it looks like it's the cam housing plugs. They're a super easy fix. I'm a ridiculously slow mechanic, partly because I enjoy taking my time and photographing stuff and using lots of rags - and drinking beer - and I changed the plugs and the separator (which is often changed at the same time) in an hour or two.
Can't tell for sure from the pictures, but it looks like it's the cam housing plugs. They're a super easy fix. I'm a ridiculously slow mechanic, partly because I enjoy taking my time and photographing stuff and using lots of rags - and drinking beer - and I changed the plugs and the separator (which is often changed at the same time) in an hour or two.
I used the aftermarket product https://www.amazon.com/gp/product/B00Z7O0Y8C and it seems to be fine. If people stress about the MB plugs being superior, well, they do seem to leak a lot.
I posted some notes on this in one of the oil consumption threads, btw.
It's not an urgent fix, but I really hate oil leaks.
You access the plugs from above. You can't see them directly, but use a mirror or your phone camera to see what's going on.
You're welcome!
Eric, thanks for the reply! That looks like a good diagnosis. Is there a chance that there is something above that that could be leaking? Only thing I can think of is valve cover gasket, but I'm just starting off on this research project! Any links to the above-mentioned thread?
Thanks again!
David from up the road in Redlands!
Eric, thanks for the reply! That looks like a good diagnosis. Is there a chance that there is something above that that could be leaking? Only thing I can think of is valve cover gasket, but I'm just starting off on this research project! Any links to the above-mentioned thread?
Thanks again!
David from up the road in Redlands!
Certainly it's the likeliest culprit.
MB engines seem to be generally very tight when it comes to gaskets and seals. I haven't heard of valve cover gaskets or head gaskets leaking.
Hope you're enjoying our little bout of non So Cal weather - staying dry but enjoying the rain.
Changed all three plugs as well as the oil separator last night. Only the one large plug was leaky, but I did the rest preventatively. I used the knock-off stuff from Amazon, will see how that works out. I couldn't get a torque wrench in there to do the separator bolts, so guessed on it. Didn't want to over-tighten on the plastic part, so went under the 10 ft/lbs spec if anything. Hardest part was dealing with the heat coming off the hot engine, otherwise a very easy and straightforward job!
Thanks for all the advice!!!
On to the front senor position seals... those are weeping. Looks to be an exciting job!!!
Check to see whether you have the upgraded magnets. If not, definitely change out with the new ones.
I was able to change the inboard (intake) magnets without too much difficulty. Had to customize a 1/4" wrench to do it. But I couldn't see how to do the exhaust without pulling the power steering pump.
Check to see whether you have the upgraded magnets. If not, definitely change out with the new ones.
I was able to change the inboard (intake) magnets without too much difficulty. Had to customize a 1/4" wrench to do it. But I couldn't see how to do the exhaust without pulling the power steering pump.
Any suggestions on how to/where to check on the magnets? First I've heard of this.
That second bank on the driver's side looks like a doozy... resigning myself to pulling the PS pump.
Any suggestions on how to/where to check on the magnets? First I've heard of this.
That second bank on the driver's side looks like a doozy... resigning myself to pulling the PS pump.
Many threads on this topic. Go thru my post history and you'll find the info. I did the swap Jan 2014; check then. This includes the old and revised part numbers, which I would share but I don't have handy. I understand that the new magnets have a wider tolerance, allowing more timing slop. I believe they are a band-aid for timing chain wear or something like that. If you get P0012, 22, 15, or 25 errors, the limits are being exceeded. 5 is the outboard magnets.
I sure wouldn't bother doing the outboard unless the oil leak was really a problem and/or I was getting OBD2 errors.
Can't tell for sure from the pictures, but it looks like it's the cam housing plugs. They're a super easy fix. I'm a ridiculously slow mechanic, partly because I enjoy taking my time and photographing stuff and using lots of rags - and drinking beer - and I changed the plugs and the separator (which is often changed at the same time) in an hour or two.
I used the aftermarket product https://www.amazon.com/gp/product/B00Z7O0Y8C and it seems to be fine. If people stress about the MB plugs being superior, well, they do seem to leak a lot.
I posted some notes on this in one of the oil consumption threads, btw.
It's not an urgent fix, but I really hate oil leaks.
You access the plugs from above. You can't see them directly, but use a mirror or your phone camera to see what's going on.
You're welcome!
I went with the aftermarket plug set, and the large one continued to leak. I replaced with a Mercedes-Benz plug, and no leakage! The smaller aftermarket plugs seem to be fine, but I'm keeping an eye on them.
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